Patent literature 1 proposes a control using a visual feedback to move an end effector to a target position by controlling the rotation of a joint of a robot based on a result of imaging the end effector by a camera. In the control by such a visual feedback, positional information of the end effector is obtained from the imaging result of the camera. The positional information of the end effector obtained in this way is converted into a rotation control amount for controlling the rotation of the joint. By controlling the rotation of the joint based on this rotation control amount, the end effector can be moved to the target position.
Further, non-patent literature 1 proposes a control law including a term for converting positional information of an end effector into a torque of a joint as a rotation control amount. This control law includes a kinematic operation term for converting the positional information of the end effector into the torque of the joint by operating a transposed Jacobian matrix to a positional deviation e (positional information) between an actual position X and a target position Xd of the end effector. By this operation term, a torque executing a proportional control based on the positional deviation e (=Xd−X) of the end effector (proportional torque based on the positional deviation) acts on the joint to rotate the joint in a direction to reduce the positional deviation e and move the end effector to the target position Xd. Further, the positional deviation e obtained from the imaging result of the camera may be applied to the operation term of the control law to apply this control law to a robot control by the visual feedback.